On October 17, 1989 at 5:04pm local time, an earthquake with a surface magnitude of 7.1 occurred along the San Andreas Fault zone. The epicenter was in Forest of Nisene Marks State Park in Santa Cruz County which was 10 miles northeast of Santa Cruz.
Although San Francisco and Oakland were located 60 miles northwest of the epicenter, these two cities suffered billions of dollars of damage.
Another Name: Loma Prieta Earthquake
The quake was named Loma Prieta after a mountain peak located 5 miles to the northeast of the epicenter. This was the largest earthquake to occur on the San Andreas Fault since the Great San Francisco Earthquake of 1906.
Scientists analyzed the motion of the earthquake and concluded that it occurred on a sub-parallel fault. This leads them to believe that there will be more damaging seismic activity along the San Andreas Fault.
Another Name: World Series Earthquake
This earthquake has also been nicknamed the World Series Earthquake because it occurred during the warm up for the third game of the World Series between the Oakland Athletics and the San Francisco Giants in Candlestick Park.
Millions of people were watching the game on TV. All of a sudden the screen went blank for no known reason. Several minutes later, audio was restored and that is when the world found out about the earthquake. When video was restored, the sports broadcasters began to show live reports of the damage endured in San Francisco.
Damage Caused by the 1989 San Francisco Earthquake
San Francisco’s Marina District suffered extensive damage. This was due to the unsteadiness of the ground. Following the 1906 San Francisco Earthquake, the debris and rubble was dumped into this area. Because this was filled land, the shockwaves were more severe. Buildings easily collapsed and buckled. Five people died.
Water mains broke and utility lines were severed. Ruptured gas mains caused fires. By luck the fire boat Phoenix was able to pump water from the bay into the fire hoses to use on land. The fireboat was also used in the 1906 earthquake.
A portion of the Cypress Street Viaduct collapsed on the Nimitz Freeway where the upper deck collapsed and crushed the cars on the lower deck. There were 42 fatalities.
On the San Francisco-Oakland Bay Bridge, a 50 foot section of the upper deck gave way and fell to the lower deck. One person was killed.
Many waterfront properties suffered damage because of using landfill. Towns in surrounding counties also had collapsed buildings, landslides and ground ruptures.
In the town of Santa Cruz which was close to the epicenter, 40 buildings collapsed and six people were killed. The Pacific Garden Mall in the downtown area tumbled down on people exiting the buildings.
Statistics of the 1989 San Francisco Earthquake
- Deaths: 67
- Injuries: 3,757
- Homeless: more than 12,000
- Property Damage: $ 5,900,000,000. At the time, this was the most costly natural disaster in the United States.
Interesting Facts About the 1989 San Francisco Earthquake
Because of the World Series game being held that evening, many people left work early or gathered at restaurants to watch the game. This made the rush hour traffic lighter than normal; otherwise, the death toll could have been much higher.
At Candlestick Park, only half of the fans had arrived when the earthquake hit. This helped reduce the load and strain on the stadium structure. A seismic strengthening project had recently been completed on the upper deck of the stadium. The stadium was not damaged and the fans rode the wave and wanted the game to begin. It didn’t happen; the game was postponed for 10 days.
The Goodyear Blimp was hovering over Candlestick Park and it was put to use by flying over the city and taking aerial shots. Not only did it keep television networks up to date, it helped guide emergency workers to critical areas requiring their services. From a scientific aspect, the blimp bounced during the quake and the sensors picked up the motion. This was the first concrete evidence that an air column is created above an earthquake.
In the days leading up to the earthquake, scientists noticed changes in the magnetic field and radio signals in the Santa Cruz Mountains. There were observations of unusual tides and gravitational force data was showing abnormal readings.
Apparently, a retired geologist wrote a newspaper article four days prior to the quake with a prediction of an earthquake during the World Series. On the day of the earthquake a reporter published an off-the-cuff remark in the morning newspaper about an earthquake ripping through the Bay Area before they sing the national anthem. The rest is history.
Sources:
- Berkeley Seismology
- BBC UK
Related Articles on Earthquakes in California:
1906 San Francisco Earthquake: Quake in Bay Area Among Worst Natural Disasters Recorded in the US. A severe rupture occurred along the San Andreas Fault near San Francisco and tremors were felt in Oregon, southern California and central Nevada.
The Long Beach Earthquake 1933: Widespread Damage to Buildings and Schools in Southern California. Poorly constructed buildings, without reinforcement, toppled from Los Angeles to Laguna Beach, resulting in legislation to make structures more earthquake-resistant.
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